diff --git a/.github/workflows/build-win-2.yml b/.github/workflows/build-win-2.yml
index 61b157a4..85643072 100644
--- a/.github/workflows/build-win-2.yml
+++ b/.github/workflows/build-win-2.yml
@@ -1,27 +1,37 @@
 name: Emu build 2 (Windows)
 
 on:
-  push:
-    branches: [ 
-      "ci-build-emu-win*",
-      "ci-build-all"
-    ]
-    tags:        
-      - release*
+  workflow_call:
+    inputs:
+      emu-variant:
+        description: |
+          Which variant of the emu to build:
+            regular: build the regular version of the emu
+            exp: build the experimental version of the emu
+            client: build the experimental steamclient version of the emu
+            tools: build the tools only
+            all: build all variants
+        default: 'all'
+        required: false
+        type: string
+
+      x32:
+        description: |
+          build architecture, unused when 'emu-variant' == 'all' or 'emu-variant' == 'tools'
+            true: x32
+            false: x64
+        default: false
+        required: false
+        type: boolean
     
-  pull_request:
-    branches: [ "dev" ]
-    paths-ignore:
-      - '**/*.md'
-      - 'dev.notes/**'
-      - 'post_build/**'
-      - 'z_original_repo_files/**'
-      - 'sdk/*.txt'
-      - 'LICENSE'
-      # tools
-      - 'tools/generate_emu_config/**'
-      - 'tools/migrate_gse/**'
-      - 'tools/steamclient_loader/linux/**'
+      debug:
+        description: |
+          build mode, unused when 'emu-variant' == 'all'
+            true: build in debug mode
+            false: build in release mode
+        default: false
+        required: false
+        type: boolean
     
   workflow_dispatch:
     # allows manual trigger
@@ -37,8 +47,8 @@ env:
   THIRD_PARTY_BASE_DIR: 'third-party'
 
 jobs:
-  # this helps in manual runs, if build fails, then deps are saved
   dependencies:
+    name: Restore or build deps
     if: ${{ !cancelled() }}
     uses: ./.github/workflows/deps-win.yml
 
@@ -48,7 +58,46 @@ jobs:
     needs: [ dependencies ]
     if: ${{ !cancelled() }}
     steps:
-    # on Windows Git will auto change line ending to CRLF, not preferable
+### setup build vars
+    - name: Setup build vars
+      shell: cmd
+      run: |
+        echo env file = "${{ GITHUB_ENV }}"
+        
+        if /i "${{ inputs.debug }}"=="true" (
+          set "build_switches=%build_switches% debug"
+          >>"${{ GITHUB_ENV }}" echo build_mode=debug
+        ) else (
+          >>"${{ GITHUB_ENV }}" echo build_mode=release
+        )
+
+        set "arch="
+        if /i "${{ inputs.x32 }}"=="true" (
+          set "arch=32"
+        ) else (
+          set "arch=64"
+        )
+
+        set "build_switches="
+        if "${{ inputs.emu-variant }}"=="regular" (
+          set "build_switches=+lib-%arch%"
+        ) else if "${{ inputs.emu-variant }}"=="exp" (
+          set "build_switches=+ex-lib-%arch% +ex-client-%arch%"
+        ) else if "${{ inputs.emu-variant }}"=="client" (
+          set "build_switches=+exclient-%arch% +exclient-ldr-%arch% +exclient-extra-%arch% +lib-gameoverlay-%arch%"
+        ) else if "${{ inputs.emu-variant }}"=="tools" (
+          set "build_switches=+tool-itf +tool-lobby"
+        ) else if "${{ inputs.emu-variant }}"=="all" (
+          set "build_switches=+lib-32 +lib-64 +ex-lib-32 +ex-lib-64 +ex-client-32 +ex-client-64 +exclient-32 +exclient-64 +exclient-ldr-32 +exclient-ldr-64 +tool-itf +tool-lobby +exclient-extra-32 +exclient-extra-64 +lib-gameoverlay-32 +lib-gameoverlay-64"
+        ) else (
+          1>&2 echo [X] invalid emu variant "${{ inputs.emu-variant }}"
+          exit /b 1
+        )
+        
+        echo final build switches %build_switches%
+        >>"${{ GITHUB_ENV }}" echo build_switches=%build_switches%
+
+### on Windows Git will auto change line ending to CRLF, not preferable
     - name: Ensure LF line ending
       shell: cmd
       working-directory: ${{ github.workspace }}
@@ -61,7 +110,7 @@ jobs:
       uses: actions/checkout@v4
 
 ### deps
-    - name: Lookup cache for deps
+    - name: Restore deps
       id: emu-deps-cache-step
       uses: actions/cache@v4
       with:
@@ -87,54 +136,44 @@ jobs:
         ref: 'third-party/build/win'
         path: "${{env.THIRD_PARTY_BASE_DIR}}/build/win"
 
-### build (release mode)
-    - name: Build release mode
+### build target(s)
+    - name: Build target(s)
+      if: inputs.emu-variant != 'all'
       shell: cmd
       working-directory: ${{ github.workspace }}
-      run: build_win.bat -verbose release +build_str ${{ github.sha }} +exclient-extra-32 +exclient-extra-64 +lib-gameoverlay-32 +lib-gameoverlay-64
+      run: build_win.bat -verbose ${{ env.build_mode }} clean +build_str ${{ github.sha }} ${{ env.build_switches }}
 
-### package (release mode)
-    - name: Package build (release)
+### build all
+    - name: Build all
+      if: inputs.emu-variant == 'all'
       shell: cmd
       working-directory: ${{ github.workspace }}
-      run: package_win.bat release
+      run: |
+        build_win.bat -verbose release clean +build_str ${{ github.sha }} ${{ env.build_switches }} || exit /b %errorlevel%
+        build_win.bat -verbose debug clean +build_str ${{ github.sha }} ${{ env.build_switches }} || exit /b %errorlevel%
+
+### package target(s)
+    - name: Package target(s)
+      if: inputs.emu-variant != 'all'
+      shell: cmd
+      working-directory: ${{ github.workspace }}
+      run: package_win.bat ${{ env.build_mode }}
+
+### package all
+    - name: Package all
+      if: inputs.emu-variant == 'all'
+      shell: cmd
+      working-directory: ${{ github.workspace }}
+      run: |
+        package_win.bat release || exit /b %errorlevel%
+        package_win.bat debug || exit /b %errorlevel%
 
 ### upload artifact/package to github Actions (release mode)
-    - name: Upload build package (release)
+    - name: Upload build package
       uses: actions/upload-artifact@v4
       with:
         name: "build-win-release-${{ github.sha }}"
-        path: "${{ env.PACKAGE_BASE_DIR }}/release/"
+        path: "${{ env.PACKAGE_BASE_DIR }}/"
         if-no-files-found: 'error'
         compression-level: 9
         retention-days: 1
-    
-### build (debug mode)
-    - name: Build debug mode
-      shell: cmd
-      working-directory: ${{ github.workspace }}
-      run: build_win.bat -verbose debug +build_str ${{ github.sha }} +exclient-extra-32 +exclient-extra-64 +lib-gameoverlay-32 +lib-gameoverlay-64
-
-### package (debug mode)
-    - name: Package build (debug)
-      shell: cmd
-      working-directory: ${{ github.workspace }}
-      run: package_win.bat debug
-
-### upload artifact/package to github Actions (debug mode)
-    - name: Upload build package (debug)
-      uses: actions/upload-artifact@v4
-      with:
-        name: "build-win-debug-${{ github.sha }}"
-        path: "${{ env.PACKAGE_BASE_DIR }}/debug/"
-        if-no-files-found: 'error'
-        compression-level: 9
-        retention-days: 1
-    
-### release (debug + release modes) if this is a tag push
-    - name: Release
-      if: startsWith(github.ref, 'refs/tags/')
-      uses: softprops/action-gh-release@v1
-      with:
-        files: "${{ env.PACKAGE_BASE_DIR }}/**/*"
-    
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c435e9ac..d1aa5b9d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 * for Windows ColdClientLoader: allow loading `.ini` file with the same name as the loader  
   ex: if the loader is named `game_cold_loader.exe`, then it will first try to load `game_cold_loader.ini`,  
   if that doesn't exist, it will fallback to `ColdClientLoader.ini`
+* make all build switches opt-in
 
 ---
 
diff --git a/README.md b/README.md
index 0ce7d09e..6d2e6b59 100644
--- a/README.md
+++ b/README.md
@@ -153,25 +153,25 @@ Arguments you can pass to this script:
 
 >>>>>>>>>  ___
 
-* `-lib-32`: prevent building normal `steam_api.dll`
-* `-lib-64`: prevent building normal `steam_api64.dll`
+* `+lib-32`: build normal `steam_api.dll`
+* `+lib-64`: build normal `steam_api64.dll`
 
 >>>>>>>>>  ___
 
-* `-ex-lib-32`: prevent building experimental `steam_api.dll`
-* `-ex-lib-64`: prevent building experimental `steam_api64.dll`
+* `+ex-lib-32`: build experimental `steam_api.dll`
+* `+ex-lib-64`: build experimental `steam_api64.dll`
 
 >>>>>>>>>  ___
 
-* `-ex-client-32`: prevent building experimental `steamclient.dll`
-* `-ex-client-64`: prevent building experimental `steamclient64.dll`
+* `+ex-client-32`: build experimental `steamclient.dll`
+* `+ex-client-64`: build experimental `steamclient64.dll`
 
 >>>>>>>>>  ___
 
-* `-exclient-32`: prevent building steamclient `steamclient.dll`
-* `-exclient-64`: prevent building steamclient `steamclient64.dll`
-* `-exclient-ldr-32`: prevent building steamclient loader (32) `steamclient_loader_32.exe`
-* `-exclient-ldr-64`: prevent building steamclient loader (64) `steamclient_loader_64.exe`
+* `+exclient-32`: build steamclient `steamclient.dll`
+* `+exclient-64`: build steamclient `steamclient64.dll`
+* `+exclient-ldr-32`: build steamclient loader (32) `steamclient_loader_32.exe`
+* `+exclient-ldr-64`: build steamclient loader (64) `steamclient_loader_64.exe`
 
 >>>>>>>>>  ___
 
@@ -180,8 +180,8 @@ Arguments you can pass to this script:
 
 >>>>>>>>>  ___
 
-* `-tool-itf` prevent building the tool `find_interfaces`
-* `-tool-lobby`: prevent building the tool `lobby_connect`
+* `+tool-itf` build the tool `find_interfaces`
+* `+tool-lobby`: build the tool `lobby_connect`
 
 >>>>>>>>>  ___
 
@@ -218,31 +218,31 @@ Arguments you can pass to this script:
 
 >>>>>>>>>  ___
 
-* `-lib-32`: prevent building normal 32-bit `libsteam_api.so`
-* `-lib-64`: prevent building normal 64-bit `libsteam_api.so`
+* `+lib-32`: build normal 32-bit `libsteam_api.so`
+* `+lib-64`: build normal 64-bit `libsteam_api.so`
 
 >>>>>>>>>  ___
 
-* `-exp-lib-32`: prevent building experimental 32-bit `libsteam_api.so`
-* `-exp-lib-64`: prevent building experimental 64-bit `libsteam_api.so`
-* `-exp-client-32`: prevent building experimental steam client 64-bit `steamclient.so`
-* `-exp-client-64`: prevent building experimental steam client 64-bit `steamclient.so`
+* `+exp-lib-32`: build experimental 32-bit `libsteam_api.so`
+* `+exp-lib-64`: build experimental 64-bit `libsteam_api.so`
+* `+exp-client-32`: build experimental steam client 64-bit `steamclient.so`
+* `+exp-client-64`: build experimental steam client 64-bit `steamclient.so`
 
 >>>>>>>>>  ___
 
-* `-client-32`: prevent building steam client 32-bit `steamclient.so`
-* `-client-64`: prevent building steam client 64-bit `steamclient.so`
+* `+client-32`: build steam client 32-bit `steamclient.so`
+* `+client-64`: build steam client 64-bit `steamclient.so`
 
 >>>>>>>>>  ___
 
-* `-tool-clientldr`: prevent copying the tool `steamclient_loader`
+* `+tool-clientldr`: copy the tool `steamclient_loader`
 
 >>>>>>>>>  ___
 
-* `-tool-itf-32`: prevent building the tool 32-bit `find_interfaces`
-* `-tool-itf-64`: prevent building the tool 64-bit `find_interfaces`
-* `-tool-lobby-32`: prevent building the tool 32-bit `lobby_connect`
-* `-tool-lobby-64`: prevent building the tool 64-bit `lobby_connect`
+* `+tool-itf-32`: build the tool 32-bit `find_interfaces`
+* `+tool-itf-64`: build the tool 64-bit `find_interfaces`
+* `+tool-lobby-32`: build the tool 32-bit `lobby_connect`
+* `+tool-lobby-64`: build the tool 64-bit `lobby_connect`
 
 >>>>>>>>>  ___
 
diff --git a/build_linux.sh b/build_linux.sh
index 362b0ece..edd22d48 100644
--- a/build_linux.sh
+++ b/build_linux.sh
@@ -15,21 +15,21 @@ for emu_file in "${required_files[@]}"; do
   fi
 done
 
-BUILD_LIB32=1
-BUILD_LIB64=1
-BUILD_EXP_LIB32=1
-BUILD_EXP_LIB64=1
+BUILD_LIB32=0
+BUILD_LIB64=0
+BUILD_EXP_LIB32=0
+BUILD_EXP_LIB64=0
 
-BUILD_CLIENT32=1
-BUILD_CLIENT64=1
-BUILD_EXPT_CLIENT32=1
-BUILD_EXPT_CLIENT64=1
-BUILD_TOOL_CLIENT_LDR=1
+BUILD_CLIENT32=0
+BUILD_CLIENT64=0
+BUILD_EXPT_CLIENT32=0
+BUILD_EXPT_CLIENT64=0
+BUILD_TOOL_CLIENT_LDR=0
 
-BUILD_TOOL_FIND_ITFS32=1
-BUILD_TOOL_FIND_ITFS64=1
-BUILD_TOOL_LOBBY32=1
-BUILD_TOOL_LOBBY64=1
+BUILD_TOOL_FIND_ITFS32=0
+BUILD_TOOL_FIND_ITFS64=0
+BUILD_TOOL_LOBBY32=0
+BUILD_TOOL_LOBBY64=0
 
 BUILD_LIB_NET_SOCKETS_32=0
 BUILD_LIB_NET_SOCKETS_64=0
@@ -63,32 +63,32 @@ for (( i=1; i<=$#; i++ )); do
       echo "[X] Expected a build string" >&2;
       exit 1;
     }
-  elif [[ "$var" = "-lib-32" ]]; then
-    BUILD_LIB32=0
-  elif [[ "$var" = "-lib-64" ]]; then
-    BUILD_LIB64=0
-  elif [[ "$var" = "-exp-lib-32" ]]; then
-    BUILD_EXP_LIB32=0
-  elif [[ "$var" = "-exp-lib-64" ]]; then
-    BUILD_EXP_LIB64=0
-  elif [[ "$var" = "-client-32" ]]; then
-    BUILD_CLIENT32=0
-  elif [[ "$var" = "-client-64" ]]; then
-    BUILD_CLIENT64=0
-  elif [[ "$var" = "-exp-client-32" ]]; then
-    BUILD_EXPT_CLIENT32=0
-  elif [[ "$var" = "-exp-client-64" ]]; then
-    BUILD_EXPT_CLIENT64=0
-  elif [[ "$var" = "-tool-clientldr" ]]; then
-    BUILD_TOOL_CLIENT_LDR=0
-  elif [[ "$var" = "-tool-itf-32" ]]; then
-    BUILD_TOOL_FIND_ITFS32=0
-  elif [[ "$var" = "-tool-itf-64" ]]; then
-    BUILD_TOOL_FIND_ITFS64=0
-  elif [[ "$var" = "-tool-lobby-32" ]]; then
-    BUILD_TOOL_LOBBY32=0
-  elif [[ "$var" = "-tool-lobby-64" ]]; then
-    BUILD_TOOL_LOBBY64=0
+  elif [[ "$var" = "+lib-32" ]]; then
+    BUILD_LIB32=1
+  elif [[ "$var" = "+lib-64" ]]; then
+    BUILD_LIB64=1
+  elif [[ "$var" = "+exp-lib-32" ]]; then
+    BUILD_EXP_LIB32=1
+  elif [[ "$var" = "+exp-lib-64" ]]; then
+    BUILD_EXP_LIB64=1
+  elif [[ "$var" = "+client-32" ]]; then
+    BUILD_CLIENT32=1
+  elif [[ "$var" = "+client-64" ]]; then
+    BUILD_CLIENT64=1
+  elif [[ "$var" = "+exp-client-32" ]]; then
+    BUILD_EXPT_CLIENT32=1
+  elif [[ "$var" = "+exp-client-64" ]]; then
+    BUILD_EXPT_CLIENT64=1
+  elif [[ "$var" = "+tool-clientldr" ]]; then
+    BUILD_TOOL_CLIENT_LDR=1
+  elif [[ "$var" = "+tool-itf-32" ]]; then
+    BUILD_TOOL_FIND_ITFS32=1
+  elif [[ "$var" = "+tool-itf-64" ]]; then
+    BUILD_TOOL_FIND_ITFS64=1
+  elif [[ "$var" = "+tool-lobby-32" ]]; then
+    BUILD_TOOL_LOBBY32=1
+  elif [[ "$var" = "vtool-lobby-64" ]]; then
+    BUILD_TOOL_LOBBY64=1
   elif [[ "$var" = "+lib-netsockets-32" ]]; then
     BUILD_LIB_NET_SOCKETS_32=1
   elif [[ "$var" = "+lib-netsockets-64" ]]; then
diff --git a/build_win.bat b/build_win.bat
index d7992eea..acfd7229 100644
--- a/build_win.bat
+++ b/build_win.bat
@@ -17,24 +17,24 @@ for %%A in (
     )
 )
 
-set /a BUILD_LIB32=1
-set /a BUILD_LIB64=1
+set /a BUILD_LIB32=0
+set /a BUILD_LIB64=0
 
-set /a BUILD_EXP_LIB32=1
-set /a BUILD_EXP_LIB64=1
-set /a BUILD_EXP_CLIENT32=1
-set /a BUILD_EXP_CLIENT64=1
+set /a BUILD_EXP_LIB32=0
+set /a BUILD_EXP_LIB64=0
+set /a BUILD_EXP_CLIENT32=0
+set /a BUILD_EXP_CLIENT64=0
 
-set /a BUILD_EXPCLIENT32=1
-set /a BUILD_EXPCLIENT64=1
-set /a BUILD_EXPCLIENT_LDR_32=1
-set /a BUILD_EXPCLIENT_LDR_64=1
+set /a BUILD_EXPCLIENT32=0
+set /a BUILD_EXPCLIENT64=0
+set /a BUILD_EXPCLIENT_LDR_32=0
+set /a BUILD_EXPCLIENT_LDR_64=0
 
 set /a BUILD_EXPCLIENT_EXTRA_32=0
 set /a BUILD_EXPCLIENT_EXTRA_64=0
 
-set /a BUILD_TOOL_FIND_ITFS=1
-set /a BUILD_TOOL_LOBBY=1
+set /a BUILD_TOOL_FIND_ITFS=0
+set /a BUILD_TOOL_LOBBY=0
 
 set /a BUILD_LIB_NET_SOCKETS_32=0
 set /a BUILD_LIB_NET_SOCKETS_64=0
@@ -58,34 +58,34 @@ set /a VERBOSE=0
 :args_loop
   if "%~1"=="" (
     goto :args_loop_end
-  ) else if "%~1"=="-lib-32" (
-    set /a BUILD_LIB32=0
-  ) else if "%~1"=="-lib-64" (
-    set /a BUILD_LIB64=0
-  ) else if "%~1"=="-ex-lib-32" (
-    set /a BUILD_EXP_LIB32=0
-  ) else if "%~1"=="-ex-lib-64" (
-    set /a BUILD_EXP_LIB64=0
-  ) else if "%~1"=="-ex-client-32" (
-    set /a BUILD_EXP_CLIENT32=0
-  ) else if "%~1"=="-ex-client-64" (
-    set /a BUILD_EXP_CLIENT64=0
-  ) else if "%~1"=="-exclient-32" (
-    set /a BUILD_EXPCLIENT32=0
-  ) else if "%~1"=="-exclient-64" (
-    set /a BUILD_EXPCLIENT64=0
-  ) else if "%~1"=="-exclient-ldr-32" (
-    set /a BUILD_EXPCLIENT_LDR_32=0
-  ) else if "%~1"=="-exclient-ldr-64" (
-    set /a BUILD_EXPCLIENT_LDR_64=0
+  ) else if "%~1"=="+lib-32" (
+    set /a BUILD_LIB32=1
+  ) else if "%~1"=="+lib-64" (
+    set /a BUILD_LIB64=1
+  ) else if "%~1"=="+ex-lib-32" (
+    set /a BUILD_EXP_LIB32=1
+  ) else if "%~1"=="+ex-lib-64" (
+    set /a BUILD_EXP_LIB64=1
+  ) else if "%~1"=="+ex-client-32" (
+    set /a BUILD_EXP_CLIENT32=1
+  ) else if "%~1"=="+ex-client-64" (
+    set /a BUILD_EXP_CLIENT64=1
+  ) else if "%~1"=="+exclient-32" (
+    set /a BUILD_EXPCLIENT32=1
+  ) else if "%~1"=="+exclient-64" (
+    set /a BUILD_EXPCLIENT64=1
+  ) else if "%~1"=="+exclient-ldr-32" (
+    set /a BUILD_EXPCLIENT_LDR_32=1
+  ) else if "%~1"=="+exclient-ldr-64" (
+    set /a BUILD_EXPCLIENT_LDR_64=1
   ) else if "%~1"=="+exclient-extra-32" (
     set /a BUILD_EXPCLIENT_EXTRA_32=1
   ) else if "%~1"=="+exclient-extra-64" (
     set /a BUILD_EXPCLIENT_EXTRA_64=1
-  ) else if "%~1"=="-tool-itf" (
-    set /a BUILD_TOOL_FIND_ITFS=0
-  ) else if "%~1"=="-tool-lobby" (
-    set /a BUILD_TOOL_LOBBY=0
+  ) else if "%~1"=="+tool-itf" (
+    set /a BUILD_TOOL_FIND_ITFS=1
+  ) else if "%~1"=="+tool-lobby" (
+    set /a BUILD_TOOL_LOBBY=1
   ) else if "%~1"=="+lib-netsockets-32" (
     set /a BUILD_LIB_NET_SOCKETS_32=1
   ) else if "%~1"=="+lib-netsockets-64" (